The present invention pertains to a shifting device for shifting between different operating states of a motor vehicle transmission, with a gear shift lever, which is mounted movably in a bracket and can be moved in a first direction between two shift gates and which can also be moved in a second direction along a first of two shift gates into three shift positions, with a signal transmitter for sending a transmitter signal, and with three sensors arranged at spaced locations from the signal transmitter and in the form of a triangle for detecting the transmitter signal, wherein the sensors and the signal transmitter can be moved in relation to one another by means of the gearshift lever, and electric signals characterizing the particular shift position are sent by the sensors at least indirectly to an evaluator, by which the transmission can be put into different operating states as a function of the electric signals
Such shifting devices have been known from the state of the art. A shifting device with a pivotably mounted gearshift lever, which can be shifted between two shift gates, namely, between a main path and an auxiliary path, by a pivoting movement in a first direction, is disclosed in DE 694 08 356 T2 (EP 0 620 385 B1). Furthermore, the gearshift lever can be pivoted into different shift positions in a second direction extending at right angles to the first direction, the different shift positions of the gearshift lever being detected by means of four sensors and four signal transmitters. The four sensors are arranged here on a plate fixed in the housing of the shifting device, and the four signal transmitters are fixed on a movable plate, which is located above the fixed plate and is coupled with the gearshift lever. The sensors are designed as Hall sensors and the signal transmitters as magnets, wherein the Hall sensors send electric signals corresponding to the particular shift position to an electronic module, which actuates the transmission by means of actuators. One of these sensors is arranged such that it can be determined by means of this sensor whether the gearshift lever is shifted into the main path or into the auxiliary path.
Based on this prior art, the basic object of the present invention is to provide a shifting device of the type mentioned in the introduction, whose design and manufacture are simplified.
The shifting device according to the present invention for shifting between different operating states of the motor vehicle transmission has a gearshift lever, which is mounted movably in a bracket and can be moved in a first direction between two shift gates and can be additionally moved into three shift positions in a second direction along a first of the shift gates. The shifting device has a signal transmitter for sending a transmitter signal and at least three sensors arranged at spaced locations from the signal transmitter and in the form of a triangle for detecting the transmitter signal. The sensors and the signal transmitter can be moved in relation to one another by means of the gearshift lever, and the electric signals characterizing the particular shift position are sent by the sensors at least indirectly to an evaluating means, by means of which the transmission can be put into different operating states as a function of the electric signals. The signal transmitter is designed such that at the site of the sensors, the transmitter signal sweeps an area that is larger than or equal to the area of a rectangle, in which the triangle can be congruently imaged, one side of the rectangle extending in parallel to the first shift gate, and all three sensors are in interaction with the transmitter signal in a first of the three shift positions.
The different shift positions of the gearshift lever in the first shift gate can be recognized by the signal transmitter and the sensors arranged in the form of a triangle (triangular arrangement) being able to be moved or displaced by means of the gearshift lever relative to one another. Depending on the shift position, different combinations of the sensors are in interaction with the transmitter signal, so that the shift position particularly assumed can be unambiguously determined on the basis of the electric signals sent by the sensors. Thus, the transmitter signal has at least such a signal intensity over the entire swept area that the sensors can be in interaction with the transmitter signal.
The shifting device according to the present invention has only a single signal transmitter for three sensors, and the number of components is therefore reduced, and the design is thus simplified. Since it is not necessary to position and fasten a plurality of signal transmitters on one plate, the manufacture of the shifting device according to the present invention is also simplified.
If the area swept by the transmitter is larger than the area of the rectangle, the swept area may also deviate from the rectangular shape.
If the signal transmitter is designed such that the area through which the transmitter signal flows also increases with increasing distance from the signal transmitter, the active area of the signal transmitter that sends the transmitter signal may be smaller than the area of the rectangle. However, the active area of the signal transmitter may also be approximately equal to the area of the rectangle, so that the effort needed for dimensioning the active area with respect to the triangular arrangement is reduced.
The sensors may be provided on a printed circuit board fastened to the gearshift lever, and the signal transmitter may be provided on the bracket of the shifting device. However, the sensors are preferably arranged on the bracket and the signal transmitter on the gearshift lever. Since the signal transmitter is usually provided with only a few electric connections or with no electric connections at all, but each sensor has at least two electric connections, the effort needed for the electric wiring along the movable gearshift lever is reduced by this preferred arrangement.
The sensors may be fastened on a flat printed circuit board. However, the movement of the sensors fastened to the gearshift lever and of the signal transmitter fastened to the gearshift lever takes place on a curved path in the case of a pivotably mounted gearshift lever. To ensure that the distance between the sensors and the signal transmitter as viewed from the pivoting mount of the gearshift lever is affected by the pivoting movement of the gearshift lever, the sensors are preferably arranged on a curved printed circuit board, whose curvature corresponds to the curved pivoting path of the gearshift lever. As a result, the interaction between the signal transmitter and the sensors can be improved.
The signal transmitter may be an illumination source or a reflector illuminated by an illumination source, the sensors being designed as optical sensors and the transmitter signal being sent in the form of optical radiation. The signal transmitter and the sensors are not limited to the visible spectrum of the electromagnetic waves, but they may also interact with one another by means of, e.g., infrared rays. A magnet may also be provided as a signal transmitter, in which case the transmitter signal is sent in the form of a magnetic field. The magnet may be designed as an electromagnet, which is supplied with power via electric lines. However, a permanent magnet is preferably provided as a signal transmitter, in which case the sensors are formed by Hall sensors. No electric connections are necessary for operating the signal transmitter in the case of a permanent magnet, so that the effort needed for wiring is, on the whole, reduced.
The three shift positions in the first shift gate can be used to shift the transmission of the motor vehicle up or down by one or more gears without having to leave the first shift gate with the gearshift lever. A front shift position of the three shift positions is intended for upshifting and a rear shift position of the three shift positions is intended for downshifting the gears. The three shift positions are located on a straight line, and the mounting of the gearshift lever is designed such that the middle shift position forms a stable middle position between the front and rear shift positions. The front and rear shift positions are now designed as unstable shift positions, so that the gearshift lever automatically returns into the middle shift position when the gearshift lever is let go or released by the user in a shift position other than the middle shift position. Since the arrangement of the sensors is in relationship with the shift positions of the gearshift lever, the three sensors are preferably arranged in the form of an isosceles triangle, and the side of the triangle enclosed between the equal sides extends in parallel to the first shift gate. It is achieved by this arrangement of the sensors that the same distance is provided between the front and middle shift positions as between the middle and rear shift positions.
If the corner points of the triangle formed by the sensors are projected onto the straight line defined by the second direction in the shifting device according to the present invention, the image points of the corner points generated by the projection form a row of three points arranged at spaced locations from one another on this straight line. It can be recognized with the sensor associated with the middle image point whether the gearshift lever has been moved into the first shift gate, and this sensor is therefore also called the shift gate sensor. The individual shift positions in the first shift gate can be recognized with the sensors associated with the outer image points, and these sensors are therefore also called shift position sensors.
The two shift position sensors would, in principle, be sufficient for detecting the three shift positions in the first shift gate. However, a safety-increasing redundancy is achieved by means of the shift gate sensor provided additionally.
Regardless of the shift position, at least one of the shift position sensors is in interaction with the transmitter signal in the first shift gate, and, furthermore, the electric signal sent by the shift gate sensor carries the information that the gearshift lever has been shifted into the first shift gate. The shift gate sensor may be arranged either facing the second shift gate or facing away from same with respect to the triangle. However, if the shift gate sensor is arranged on the side of the straight line defined by the two shift position sensors, which side faces away from the second shift gate, the shift position sensors or the electric signals sent by them can be deactivated, e.g., by means of the shift gate sensor when the gearshift lever is moved out of the first shift gate, because the shift gate sensor falls out of the area affected by the transmitter signal in this arrangement of the shift gate sensors. The shift gate sensor is therefore preferably arranged on the side of the straight line defined by the two shift position sensors, which side faces away from the second shift gate.
Each of the three shift positions may be the same shift position that is assumed as the first one when the gearshift lever is shifted from the second shift gate into the first shift gate. However, the first shift position is preferably the shift position assumed first when the gearshift lever is shifted from the second shift gate into the first shift gate. According to this embodiment of the present invention, all three sensors come consequently first into interaction with the transmitter signal when the gearshift lever is moved into the first shift gate. According to another preferred embodiment of the present invention, the first shift position now also forms the middle shift position at the same time.
If the gearshift lever is moved in a direction called the forward direction from the middle shift position along the first shift gate, it reaches a second of the three shift positions. If, by contrast, the gearshift lever is moved in the direction opposite the forward direction, which is called the reverse direction, it reaches the third shift position.
In the second shift position, the shift position sensor arranged in the forward direction and the shift gate sensor are in interaction with the transmitter signal, whereas the shift position sensor arranged in the reverse direction is not in interaction with the transmitter signal. The shift position sensor arranged in the reverse direction and the shift gate sensor are in interaction with the transmitter signal in the shift position, whereas the shift position sensor arranged in the forward direction is not in interaction with the transmitter signal.
The shift gate sensor is not necessary for the mere recognition of the first, second or third shifting state, but the shifting device without shift gate sensor could have the following drawback: When the gearshift lever arranged in the first shift position is shifted out of the first shift gate, the two shift position sensors do not usually fall out of the area affected by the transmitter signal simultaneously because of inaccuracies in mounting and component tolerances. However, the electric signals sent by the sensors indicate in this case either the second shift position or the third shift position, which could cause the evaluating means to change the operating state of the transmission, even though the user only wanted to shift the gearshift lever out of the first shift gate and did not intend to change the operating state at all.
In the preferred embodiment of the present invention, when the gearshift lever is shifted out of the first shift gate, the shift gate sensor is the first sensor to drop out of the area affected by the transmitter signal before one or both of the shift position sensors fall out of the area affected by the signal transmitter and the above-mentioned drawback can occur. The change of the shift gate can thus be unambiguously recognized. The electric signals sent by the shift position sensors (shift position signals) are consequently taken into account for setting the operating state of the transmission only when the shift gate sensor is in interaction with the transmitter signal or the electric signal sent by the shift gate sensor (shift gate signal) carries the information that the gearshift lever has been brought into the first shift gate. As a result, the above-described drawback can be eliminated.
All three sensors can be continuously activated during the use of the shifting device according to the present invention, the shift position signals and the shift gate signal being sent to the evaluating means. However, the shift position sensors or the shift position signals are preferably deactivated by the shift gate sensor when the gearshift lever is pivoted out of the first shift gate and they are activated by the shift gate sensor when the gearshift lever is pivoted into the first shift gate. In this case, the shift gate signal is used as a control signal for the shift position sensors or the shift position signals, and it no longer needs to be sent to the evaluating means, so that the electric connection or line provided for this can be eliminated. As a result, the shifting device according to the present invention is made more simple and less expensive.
It is assumed for the following description of the activation and deactivation of the shift position sensors or shift position signals that the signal sent by each of the sensors has a logic H level when the energized sensor is in interaction with the transmitter signal, a logic L level when the energized sensor is not in interaction with the transmitter signal, and a logic L level or a third level at least deviating from the H level when the power supply for the sensor is switched off. The sensor is in the active state when the sensor is supplied with power and in the deactivated state when the sensor is not supplied with power.
The activation and the deactivation of the shift position sensors can be achieved, e.g., by the power supply for the shift position sensors being switched on or switched off by the shift gate sensor. Since both shift position signals have a logic L level or a third level in the deactivated state of the shift position sensors, the evaluating means can recognize solely on the basis of the shift position signals that the gearshift lever is not set into the first shift gate. If a three-state logic is used, the third level may also correspond to the high-resistance state.
The activation and the deactivation of the shift position signals can be carried out by each shift position signal being subjected to a logic AND operation with the shift gate signal. In this case, each shift position signal is sent in the form of a linked signal to the evaluating means. In the deactivated state of the shift position signal, the shift gate signal has a logic L level, as a result of which the linked signal has a logic L level. By contrast, the shift gate signal has a logic H level in the activated state of the shift position signal, so that the logic level of the linked signal always corresponds to the logic level of the shift position signal. During the activation and deactivation of the shift position signals, these signals are sent to the evaluating means indirectly, namely, in the form of linked signals.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.